In a typical consumable electrode arc welding, welding is performed by feeding a welding wire as a consumable electrode at a constant feeding rate and generating an arc between the welding wire and base material. In the consumable electrode arc welding, both the welding wire and the base material are mostly placed in a welding state in which a short-circuiting period and an arc period are alternately repeated.
In order to further improve welding quality, there has been proposed a welding method of alternating feeding of the welding wire between forward feeding and reverse feeding cyclically (see Patent Documents 1 and 2, for example).
According to the invention of the patent document 1, an average value of the feeding rate is adjusted according to a welding current setting value, and a repetition frequency and an amplitude of the forward feeding and the reverse feeding of the welding wire are adjusted to respective values according to the welding current setting value.
The invention of the patent document 2 relates to an arc welding control method of feeding the welding wire at a wire feeding rate of cyclically repeating the forward feeding and the reverse feeding with predetermined frequency and amplitude from a time point at which start of the welding is instructed and conduction of welding current is started, and then changing the wire feeding rate to a constant feeding rate.